Abstract Modern agricultural extension services help as a source of information for farmer queries. One of its applications are local hot lines where expert agents in specific crops or fields assist in farmer agricultural practices and decisions. As an already established technology in the field of customer services, conversational agents can help this solution by covering for experts when users have difficulties contacting them. These artificial agents can answer general queries at any hour, increasing the extension service accessibility. The creation of a contextualized solution is possible with the advancements of Natural Language Processing (NLP) and its accessibility in cloud services. We write this paper to collect state-of-the-art research on agricultural conversational agents and tools used for its design and deployment. General knowledge on current applications is gather and can later be used to help in the design of a localized solution when agricultural services are difficult to access. Lastly, we describe and analyze a chatbot prototype in the specific field of banana farming using IBM Watson services and the messaging platform Telegram App.

ABSTRACT Background Reduced or null expression of E-cadherin protein is a frequent cause of diffuse gastric cancer (DGC). More than 50% of patients with DGC present somatic variants in CDH1 gene. Objectives The objectives of this study were to study E-cadherin expression and identify variants in the CDH1 gene in gastric tumors of patients with DGC. Methods We studied 18 Mexican DGC patients who attended a hospital of the Mexican Social Security Institute; E-cadherin expression was determined by immunohistochemistry, and variants were identified by Sanger sequencing in promoter and coding regions. Predictive analysis was performed using PolyPhen-2 and HOPE software. Results We found that 56% of DGC patients showed reduced expression of E-cadherin. All patients carried CDH1 variants; overall, 12 different CDH1 variants were identified. Predictive analysis revealed that the rs114265540 variant was probably damaging, with a value of 0.985, indicating a functional impact on the E-cadherin protein. Variants rs34939176 and rs33964119 were identified as risk factors for DGC (odds' ratios [OR] = 31.3, 95% CI 6.3-154.0, p < 0.001; OR = 6.1, 95% CI 2.0-19.0, p < 0.001, respectively) given their elevated frequency and by comparing it with those reported for MXL population in the 1000 Genomes Project database. Conclusions In this Mexican population, the percentage of diffuse gastric tumors with reduced expression of E-cadherin was similar to that reported in other populations. All gastric tumors of DGC patients studied had somatic CDH1 gene variants; however, the rs114265540, rs34939176, and rs33964119 variants were importantly related to DGC.

ABSTRACT: The objectives were to analyze the genealogical information of Gyr (GY) and Nelore (NL) cattle from Costa Rica. Analyzed: pedigree integrity (GY, 13272; NL, 18153); number of complete, maximum traced and equivalent complete generations; inbreeding (FI); generation interval (GI) through four selection routes; average additive genetic ratio (AGR); effective number of founders (fe); effective number of ancestors (fa); effective population size (Ne). The analysis was performed with the ENDOG software. The maximum proportion of unknown parents, grandparents, and great-grandparents was 18.6%, 39.9%, and 59.3%, respectively. The average FI for NL was 8.87% and 2.85% in GY. The average consanguineous population (%) and FI was 53.9 and 16.5% in NL, 28.9 and 9.9% in GY. The average and maximum values of AGR for NL were 3.5 and 12.8, 1.4 and 5.6 in GY. The fe and fa for NL were 65.0 and 38.0, in GY 145.7 and 59.0. The Ne indicated increases in FI in the range of 1 to 2% in GY, for NL greater than 2%, with a status of care to monitor the evolution of F and AGR and their possible implications in genetic improvement. The GI ranged from 6.3 to 7.9 years with a general average of 6.9 years. These results show a summary of the genetic and reproductive management those breeders have carried out. ABSTRACT (GY (NL Rica Analyzed 13272 18153 18153) generations (FI) (GI routes (AGR) (fe) (fa) Ne. . (Ne) software parents grandparents greatgrandparents great 186 18 6 18.6% 399 39 9 39.9% 593 59 3 59.3% respectively 887 8 87 8.87 285 2 85 2.85 % (% 539 53 53. 165 16 5 16.5 289 28 28. 99 9.9 35 3. 128 12 12.8 14 4 1. 56 5. 650 65 0 65. 380 38 38.0 1457 145 7 145. 590 59.0 improvement 63 6. 79 7. 69 out 1327 1815 (FI (AGR (fe (fa (Ne 18.6 39.9 59.3 88 8.8 2.8 ( 16. 9. 12. 38. 59. 132 181 18. 39. 8. 2. 13

RESUMO: Os objetivos foram analisar as informações genealógicas de bovinos Gir (GY) e Nelore (NL) da Costa Rica. Foram considerados: integridade do pedigree (GY, 13272; NL, 18153); número de gerações completas, máximas traçadas e equivalentes completas; endogamia (FI); intervalo de geração (GI) por meio de quatro rotas de seleção; razão genética aditiva média (AGR); número efetivo de fundadores (fe); número efetivo de ancestrais (fa); tamanho efetivo da população (Ne). A análise foi realizada com o software ENDOG. A proporção máxima de pais, avós e bisavós desconhecidos foi de 18,6%, 39,9% e 59,3%, respectivamente. O FI médio para NL foi de 8,87% e 2,85% no GY. A média da população consanguínea (%) e FI foi de 53,9 e 16,5% em NL, 28,9 e 9,9% em GY. Os valores médios e máximos de AGR para NL foram 3,5 e 12,8, 1,4 e 5,6 no GY. Os fe e fa para NL foram 65,0 e 38,0, no GY 145,7 e 59,0. O Ne indicou aumentos de FI na faixa de 1 a 2% no GY, para NL superiores a 2%, com status de cuidado para acompanhar a evolução de F e AGR e suas possíveis implicações no melhoramento genético. O IG variou de 6,3 a 7,9 anos com média geral de 6,9 anos. Esses resultados mostram um resumo do manejo genético e reprodutivo realizado por esses criadores. RESUMO (GY (NL Rica considerados 13272 18153 18153) completas (FI) GI (GI seleção (AGR) (fe) (fa) Ne. . (Ne) ENDOG pais 186 18 6 18,6% 399 39 9 39,9 593 59 3 59,3% respectivamente 887 8 87 8,87 285 2 85 2,85 % (% 539 53 53, 165 16 5 16,5 289 28 28, 99 9,9 35 3, 128 12 12,8 14 4 1, 56 5, 650 65 0 65, 380 38 38,0 1457 145 7 145, 590 59,0 63 6, 79 7, 69 criadores 1327 1815 (FI (AGR (fe (fa (Ne 18,6 39, 59,3 88 8,8 2,8 ( 16, 9, 12, 38, 59, 132 181 18, 8, 2, 13

Los síndromes coronaries crónicos son infrecuentes en mujeres jóvenes, quienes suelen presentar una lenta progresión de enfermedad coronaria aterosclerótica, tienen presentación clínica atípica y son menos sujetas a exploración diagnostica. Se deben considerar causas no ateroscleróticas de enfermedad coronaria en mujeres jóvenes con angina. Informamos una paciente de 25 años que consultó por cinco meses de angina con esfuerzos moderados. Al examen físico presentaba un soplo carotideo derecho y pulsos asimétricos de extremidades superiores. La exploración de laboratorio inicial y posterior evaluación multimodal permitió evidenciar la presencia de aortitis y estenosis de ambos ostium coronarios, concordante con el diagnóstico de una arteritis de Takayasu. Inició terapia medica con respuesta clínica aparentemente favorable. No obstante, la evaluación cardiológica no invasiva en el seguimiento permitió corroborar la persistencia de isquemia significativa y necesidad de revascularización miocárdica. Se realizó una intervención coronaria percutánea de ambos ostium, con una evolución favorable.

Chronic coronary syndromes are usually considered uncommon in young women, related to slower progression of atherosclerotic coronary artery disease, have atypical clinical presentations, and experience less diagnostic investigation. Non-atherosclerotic causes of coronary artery disease should be considered in young women experiencing angina. We report a 25-year-old woman who consulted for five months of moderate exertion angina. Physical examination revealed a right carotid bruit and asymmetrical upper extremity peripheral pulses. Initial work-up and imaging allowed to diagnose aortitis with bilateral coronary ostial stenosis secondary to Takayasu's arteritis. The patient experienced an apparent clinical response to initial medical therapy. However, follow-up evaluation revealed persistence of significant ischemia and requirement for myocardial revascularization. A percutaneous coronary intervention was performed.

A simple and low-cost experimental procedure to compare the mixing and transport of two substances in water is presented in this paper, aiming to investigate if rhodamine can predict the fate of coal transport in water. The procedure is based on acoustic Doppler techniques to characterize the flow and imaging techniques to measure the transport of substances discharged from an instantaneous point source near the free surface. To validate this procedure, several tests are carried out for rhodamine and two subsamples of coal (defined by a fine and coarse granulometry) in a flume under currents. The results show that the mixing of rhodamine resembles the finest fraction of coal that is transported as a suspended material, but fails to characterize the larger coal grains that experience sedimentation. The procedure here proposed can be expanded to characterize the mixing of substances in a body of water under other conditions, such as waves or wind driven currents.

En este artículo se presenta un procedimiento experimental simple y de bajo costo para comparar la mezcla y el transporte de sustancias en el agua, con el objetivo de investigar si la rodamina puede predecir el destino del transporte de carbón en el agua. El procedimiento se basa en técnicas Doppler acústico para caracterizar el flujo y técnicas de procesamiento de imágenes para medir el transporte de sustancias descargadas desde una fuente puntual instantánea cerca de la superficie libre. Para validar el procedimiento, se realizan ensayos de rodamina y muestras de carbón (de granulometría fina y gruesa) en un canal de corrientes. Los resultados muestran que la mezcla de rodamina se asemeja a la fracción más fina de carbón transportado como material en suspensión, pero no caracteriza los granos de carbón más grandes que sedimentan. El procedimiento propuesto puede ampliarse para caracterizar la mezcla de sustancias en otras condiciones, como olas o corrientes.

RESUMEN. Introducción: Medir el bienestar de las aves bajo condiciones comerciales intensivas es complejo. El tipo de alojamiento, la naturaleza del estímulo, el tipo y tiempo de exposición, la edad, el sexo, el tiempo que tarda la evaluación y las diferencias individuales afectan los resultados. Objetivo: Evaluar el bienestar animal bajo condiciones intensivas, en galeras con ventilación natural y con ambiente controlado mediante el protocolo Welfare Quality Project (2009). Métodos: Evaluamos 22 granjas comerciales diferentes, 11 galeras con ambiente controlado y 11 galeras con ventilación natural durante el 2018 y 2019. Se aplicó el protocolo Welfare Quality Project con modificación en el principio de buena salud, por el método de transectos. Para cada criterio, aplicamos diferentes pruebas que transformamos en calificaciones mediante fórmulas proporcionadas por el instrumento denominado Spline funtions Welfare Quality. Resultados: El 54% de las granjas obtuvo calificaciones excelentes y el 46% se calificaron como buenas. Las puntuaciones más bajas las obtuvimos en las pruebas de calidad de la cama, porcentaje de cojeras, porcentaje de pododermatitis y en la prueba cualitativa de comportamiento. Encontramos diferencias estadísticamente significativas p≤0,05 entre galeras abiertas con ventilación natural y de ambiente controlado, en la calidad de la cama, porcentaje de cojeras, densidad y ausencia prolongada de hambre. Conclusiones: Todas las granjas evaluadas, en ambos sistemas de alojamiento, propiciaron el bienestar de los pollos de acuerdo con el protocolo Welfare Quality Project.

ABSTRACT. ''Commercial Level Chicken Welfare Evaluation with the Welfare Quality Project Protocol''Introduction: Measuring bird welfare under intensive commercial conditions is something complex. The type of housing, nature of the stimulus, exposure type and time, age, sex, assessment duration, and individual differences affect the results. Objective: Evaluating animal welfare under intensive conditions, in naturally ventilated and environmentally controlled sheds with the Welfare Quality Project (2009) protocol. Methods: We evaluated 22 different commercial farms, 11 environmentally controlled sheds, and 11 naturally ventilated sheds during 2018 and 2019. The Welfare Quality Project was implemented, modifying the principle of good health through the transect method. For each criterion, we applied different tests, which we transformed into scores using formulas provided by the spline function Welfare Quality instrument. Results: 54% of the farms were rated as excellent and 46% of them were rated as good. We obtained the lowest scores in the bedding quality control tests, the lameness percentage, the pododermatitis percentage, and the Qualitative Behavior Assessment (QBA). We found statistically significant differences p≤0,05 between naturally ventilated open sheds and environmentally controlled sheds in bedding quality, lameness percentage, density, and absence of prolonged hunger. Conclusion: We recommend more research on fisheries management, conservation and environmental education; and greater integration of local and international research.

ABSTRACT: Background: The Stent-Save a Life! (SSL) LATAM working group designed a survey to demonstrate the reduction in the activity of cardiac catheterization laboratories in Latin America during the COVID-19 pandemic. Considering the risk of a new confinement in Chile, we decided to assess the impact of the first wave of contagions on our activity. Aims: To discuss the repercussion of the COVID-19 pandemic on the activity of interventional cardiology in Chile. Methods: The SSL group conducted a telematic survey in all Latin American countries. Coronary angiography, coronary interventions (PCI) and structural interventions were registered, comparing two periods of two weeks duration each: before and during COVID-19 confinement. Results obtained in Chile are analyzed. Results: Thirteen centers in Chile answered the survey. There was an overall decrease of 65.1% in the number of procedures between the pre and the post COVID-19 periods. Coronary angiographies decreased 67%, PCI 59.4% and therapeutical structural procedures 92%. The reduction in acute coronary syndrome with ST segment elevation (STEMI) was 40,8% between periods. Conclusions: In Chile, a significant reduction in healthcare activity related to interventional cardiology and a significant decrease in the number of patients treated with STEMI was observed during the COVID-19 pandemic. The results are similar to those reported by Latin American, European and North American countries.

RESUMEN: Introducción: El Stent-Save a Life! (SSL) LATAM working group diseñó una encuesta para objetivar la reducción de la actividad de los laboratorios de hemodinamia en Latinoamérica durante la pandemia COVID-19. Ante la amenaza de nuevos confinamientos en Chile, nos propusimos objetivar las consecuencias de la primera ola de contagios en nuestra actividad. Objetivos: Discutir la repercusión de la pandemia en la cardiología intervencional en Chile. Métodos: El grupo SSL realizó una encuesta telemática a todos los países de Latinoamérica incluido Chile. Se registraron las coronariografías (CAG), intervenciones coronarias percutáneas (ACTP) e intervenciones estructurales, comparando dos períodos determinados por el confinamiento por la pandemia, cada uno de dos semanas. Pre-COVID-19: período previo al confinamiento, y COVID-19: período durante el confinamiento. Se analizan, a partir de esta encuesta, los resultados aplicados a nuestro país. Resultados: Se obtuvo respuesta de trece centros. Hubo una reducción en el número global de procedimientos entre período Pre-COVID-19 y COVID-19 de un 65,1%. Se reportó una disminución de 67% en las CAG, de un 59,4% en las ACTP y de un 92% en los procedimientos terapéuticos estructurales. Entre ambos períodos se redujo la consulta por Síndrome Coronario Agudo por elevación del segmento ST (SCACEST) en 40,8%. Conclusiones: En nuestro país se objetivó una reducción marcada de la actividad asistencial de la cardiología intervencional durante la pandemia COVID-19 y una disminución significativa en el número de pacientes tratados por SCACEST. Los resultados de nuestro país son similares a los reportados por países de Latinoamérica, Europa y Norteamérica.

ABSTRACT The objective of this study was to evaluate the population of Brahman cattle from Costa Rica. Pedigree analysis of 98,749 animals was used to estimate the following parameters: pedigree integrity, as a proportion of known ancestors; the number of complete generations, maximum generations traced, and equivalent complete generations; inbreeding coefficient (F); generation interval (GI) across four selection paths; additive genetic relationship (AGR); effective number of founders (fe) and ancestors (fa); and effective population size (Ne). The analysis was carried out using the ENDOG software. The maximum proportions of unknown parents, grandparents, and great-grandparents were 14.1%, 38.9%, and 61.2%, respectively. Average F for the whole population was 0.86, while 27.4% of the population was inbred, with an average F of 3.1%. The inbred population increased through the time, while F decreased. The average AGR was 0.64, with maximum values of 4.1 and positive trends. The fe and fa were 617.8 and 172.0, respectively. The Ne indicated increases of F, with values lower than 1%. The GI fluctuated from 6.4 to 7.4, with an average of 6.85 years. These results summarize previous breeding practices and represent useful information for designing breeding programs by anticipating the relationship between the selection response and increases of inbreeding.

ABSTRACT Background The coronavirus disease (COVID-19) pandemic affected the prompt diagnosis and treatment of Acute myocardial infarction (AMI). Aim: To characterize the clinical profile of patients with AMI during the COVID-19 pandemic, comparing them with a historical cohort. Material and Methods: A case-control study of 96 patients with AMI transferred to a high-volume percutaneous coronary intervention (PCI) hospital between March and July 2020, and a historical cohort of 269 patients transferred during the same period in 2019. Results: When comparing patients transferred during the pandemic with those of the historical cohort, the former were younger (63 ± 12 vs 68 ± 12 years, p < 0.01), had a higher frequency of hypertension (66 vs 45%, p < 0.01) and of smoking (40% vs 25%, p < 0.01). Also, during COVID-19 outbreak a higher proportion of patients had ST-elevation AMI consulting > 12 hours from the onset of symptoms (44 vs 0%, p < 0.01), a higher median door-to-device time (4 vs 3 hours, p < 0.01), a higher use of primary percutaneous coronary intervention (97 vs 71%, p < 0.01), and higher frequencies of cardiogenic shock (20 vs 4%, p < 0.01) and mechanical complications (10% vs 2%, p < 0.01). Patients during COVID pandemic had a higher thirty-day overall (20 vs 1.4%, p < 0.01) and cardiovascular mortality (13 vs 1%, p < 0.01). During the outbreak, 40% of patients had positive COVID-19 status, which was a predictor for thirty-day overall mortality (Risk ratio 2.90; 95% confidence intervals 1.14-7.36). Conclusions: During the pandemic patients with AMI exhibited delays in consultations and treatment, higher morbidity, and increased mortality. COVID-19 positivity was associated to worse thirty-day overall survival.

Antecedentes: La pandemia COVID-19 afectó el tratamiento oportuno del infarto agudo de miocardio (IAM). Objetivo: Caracterizar el perfil clínico de pacientes con IAM durante la pandemia COVID-19 y compararlos con una cohorte histórica. Pacientes y Métodos: Estudio caso-control de 96 pacientes con IAM transferidos a un hospital de alto volumen de intervención coronaria percutánea (ICP) entre marzo julio de 2020 y una cohorte histórica de 269 pacientes transferidos en el mismo período de 2019 (n = 269). Resultados: Al comparar los pacientes transferidos durante pandemia y la cohorte histórica, los primeros eran más jóvenes (63 ± 12 y 68 ± 12 años respectivamente, p < 0,01), tenían una mayor frecuencia de hipertensión (65.6 y 45.1% respectivamente, p < 0,01) y tabaquismo (39,6 y 25,1% respectivamente, p < 0,01). También tuvieron una consulta > 12 h desde iniciados síntomas de IAM con elevación ST (44,4 y 0% respectivamente, p < 0,01), una mediana de tiempo puerta-guía mayor (4 y 3 horas respectivamente, p < 0,01), un mayor uso de ICP primaria (97 y 71% respectivamente, p < 0,01), mayor frecuencia de shock cardiogénico (19,8 y 4,1% respectivamente, p < 0.01) y complicaciones mecánicas (10,4 y 1,7% respectivamente, p < 0,01). A treinta días, los primeros tuvieron mayor mortalidad general (19,8 y 1,4% respectivamente p < 0.01) y cardiovascular (12,5 y 1,4% respectivamente, p < 0,01). Durante la pandemia, 40% de los pacientes presentó positividad para COVID-19, siendo un factor predictivo de mortalidad general (razón de riesgo 2,90; intervalos de confianza 95% 1,14-7,36). Conclusiones: Durante la pandemia, hubo retrasos en tiempos de consulta y tratamiento y mayor morbimortalidad del IAM. La positividad de COVID-19 se asoció a peor sobrevida general a treinta días.

Spontaneous coronary artery dissection is an uncommon cause of acute coronary syndrome that predominantly affects women without cardiovascular risk factors. In transplant patients, spontaneous coronary artery dissection is an extremely rare condition, having been described in only three patients, in whom vascular damage secondary to the use of anticalcineurinics is postulated as a probable mechanism. We report a spontaneous coronary dissection in a female who received a heart transplant at 34 years of age. The diagnosis was made in a follow-up coronary angiography three years after transplantation, supplemented with optical coherence tomography. A percutaneous coronary revascularization of the involved artery was performed, with good immediate results and at one year of follow-up.

ABSTRACT Background: Cardiogenic shock (CS) is uncommon in the cardiac catheterization laboratory (CCL) among patients undergoing coronary angiography. Periprocedural CS is more frequent in high-risk patients and in technically demanding procedures. Aim: To describe the clinical outcomes of patients who underwent peripheral venoarterial extracorporeal membrane oxygenation (pVA-ECMO) for CS associated with interventional cardiology procedures. Material and Methods: Review of clinical records of seven patients treated between January 2014 and October 2018. Results: pVA-ECMO was implanted within 6 hours of the interventional cardiology procedure. All patients had coronary artery disease and one of them also had symptomatic severe aortic stenosis. One patient entered the CCL in cardiac arrest. Percutaneous coronary intervention (PCI) was performed in all patients; four patients underwent an emergency procedure and five patients experienced PCI complications. One patient undergoing transcatheter aortic valve replacement suffered acute severe aortic regurgitation. An intra-aortic balloon pump was inserted at the CCL in five patients. Six patients experienced cardiac arrest. Mean SAVE score was -4.3 and baseline lactate 55 mg/dl. pVA-ECMO mean duration was 5 ± 4 days. Survival after both hospital discharge and 12 months of follow-up was 85.7% Regarding vascular access complications, we observed one access site hematoma and one episode of cannulation site bleeding requiring surgical repair. Conclusions: pVA-ECMO should be considered in patients with periprocedural CS as a bridge to recovery. Its use was associated with improved clinical outcomes in this series.

Antecedentes: El shock cardiogénico (SC) es infrecuente en el laboratorio de cateterismo cardíaco (LCC) entre pacientes que son sometidos a coronariografía. El SC peri-procedimiento es más frecuente en pacientes de alto riesgo y en procedimientos técnicamente complejos. Objetivos: Describir los resultados clínicos de pacientes que fueron conectados a oxigenación con membrana extracorpórea veno-arterial periférica (ECMO-VAp) por SC peri-procedimiento de cardiología intervencional. Material y Métodos: Revisión de fichas clínicas de siete pacientes tratados en nuestro centro desde enero de 2014 a octubre de 2018. Resultados: ECMO-VAp fue utilizado dentro de las primeras 6 horas del procedimiento. Todos los pacientes tenían enfermedad coronaria y uno de ellos tenía además estenosis aórtica severa. Un paciente ingresó al LCC en paro cardíaco. Una intervención coronaria percutánea (ICP) fue realizada en todos los pacientes; 4 se realizaron procedimientos de emergencia y 5 pacientes tuvieron complicaciones de la ICP. A un paciente se le realizó un reemplazo valvular aórtico percutáneo y desarrolló una insuficiencia valvular aórtica aguda severa. Se instaló un balón de contrapulsación en el LCC en 5 pacientes. Seis pacientes tuvieron un paro cardiorrespiratorio. El valor del score de SAVE fue de -4,3 y el lactato basal 55 mg/dL. La duración media del ECMO-VAp fue 5 ± 4 días. La sobrevida al alta y a los 12 meses fue 85,7%. Como complicaciones del sitio de acceso vascular se observaron 1 hematoma y un episodio de sangrado que requirió reparación quirúrgica. Conclusiones: ECMO-VAp debería ser considerado en pacientes con SC peri-procedimiento como un puente a recuperación; su utilización estuvo asociada con mejoría de resultados clínicos en esta serie.

Resumen Introducción: Isla del Coco es la única isla en el Pacífico oriental con bosques tropicales húmedos, albergando 296 especies de plantas, de las cuales un 22% son endémicas. De su ecología se conoce muy poco. El bosque fue degradado con la introducción de cerdos y venados cola blanca y por deforestación. Las áreas deforestadas hace más de 120 años nunca recuperaron el bosque nativo. Objetivo: Para analizar si el área deforestada mantiene su capacidad de recuperación, se evaluó la regeneración natural y los procesos ecológicos asociados. Metodología: Desde agosto de 2016 hasta junio de 2018, se monitoreó un ensayo de restauración, establecido como un diseño de bloques completos al azar. Los tratamientos incluyeron corte de vegetación, arranque de vegetación y controles. Se utilizó una cerca de exclusión para evitar los herbívoros. Resultados: No hubo diferencias en los tratamientos de corte y arranque de la vegetación para estimular la regeneración natural. Se registró la regeneración de dos especies de árboles: 35 individuos de Cecropia pittieri y tres de Sacoglottis holdridgei, ambas endémicas. La regeneración se estableció principalmente en los primeros 15 meses. Luego de aplicados los tratamientos, la estructura y composición de la vegetación cambió de arbustos dominados por Entada gigas (28%) y Clidemia strigillosa (12%), a pastos dominados por Paspalum conjugatum (39%). Entada gigas tiene el mayor potencial de recolonización por su tasa de crecimiento de 1.6±0.2m/mes. Conclusiones: Los filtros determinados asociados con la regeneración del bosque son los herbívoros; el banco de semillas de las especies arbóreas agotado y la dispersión de semillas escasa o nula, según la especie.

Abstract Introduction: Isla del Coco is the only island in the Eastern Tropical Pacific with humid tropical forests; 296 plant species are reported, of them, 22% are endemic. Their ecology is poorly understood. Deforestation and the introduction of rats, feral pigs and white-tailed deer are the primary agents of forest degradation. After more than 120 years, the deforested areas have never recovered the native forest. Objective: To analyse if the deforested area keeps its resilience, we evaluated the natural regeneration and ecological processes associated. Methods: From August 2016 to June 2018, we conducted a restoration experiment consisting of a randomized complete blocks design including vegetation cutting, vegetation uprooting and controls as treatments. Plots were protected with an exclusion fence to avoid herbivores. Results: There were no differences between plant cutting and uprooting in stimulating natural regeneration. We only recorded the seedlings of two tree species, 35 individuals of Cecropia pittieri and three of Sacoglottis holdridgei, both endemic. Their regeneration established during the first 15 months mainly. At the end of the experiment, the structure and composition of the vegetation changed from bushes dominated by Entada gigas (28%) and Clidemia strigillosa (12%) to grasses dominated by Paspalum conjugatum (39%). Entada gigas has a high recolonizing potential with a growing rate of 1.6±0.2m/month. Conclusions: As filters for restoration we determined herbivores, which pose a strong negative impact in the development of the forest; the exhausted seed bank of tree species and scarce or null seed dispersion.

Resumen Introducción. Las investigaciones sobre el efecto del cruzamiento entre Bos indicus * Bos indicus son escasos, no obstante, el cruzamiento es una herramienta de optimización importante para el productor pecuario. Objetivo. El objetivo de este trabajo consistió en determinar el comportamiento de las características de crecimiento con base en diferentes proporciones de cruzamientos raciales Bos indicus. Materiales y métodos. El análisis se realizó con base en registros productivos de una ganadería con bovinos seleccionados Brahman y Nelore, y ganado comercial, ubicada en la región Pacífico Norte, Costa Rica. Se utilizaron los registros de 4294 animales, recopilados durante el periodo 2002-2012. Los grupos raciales incluidos en el estudio fueron: Brahman, Nelore, Gucerá, ½ Brahman ½ Nelore, ½ Brahman ½ Gucerá, ¼ Brahman ¾ Nelore y ¼ Nelore ¾ Brahman. Se evaluaron las características de peso al nacimiento, peso al destete, ganancia diaria de peso al destete, peso al año de edad, ganancia diaria de peso al año de edad, peso a los 18 meses, ganancia diaria de peso a los 18 meses, según grupo racial de la cría y de los progenitores. Adicionalmente, se analizaron los efectos no aditivos (sexo, época y año de nacimiento) y su influencia sobre las características. Resultados. Los grupos Brahman, Nelore y ¼ Nelore ¾ Brahman tuvieron los mayores pesos en todas las edades, los animales machos presentaron pesos superiores para la mayor parte de las características analizadas (P<0,05); los animales nacidos en época lluviosa presentaron los mayores pesos para todas las características, respecto a la época seca, mientras que el año de nacimiento no presentó tendencias. La raza de la madre influyó en edades tempranas de la cría y el grupo racial del padre en las diferencias posteriores al año de edad. Además, las variables sexo y época de nacimiento presentaron comportamientos definidos, mientras el año de nacimiento mostró resultados fluctuantes. Conclusión. En cruzamientos raciales Bos indicus, el grupo racial de los progenitores influencia las características de crecimiento de la progenie.

Abstract Introduction. There is little research about the effect of crossbred between Bos indicus * Bos indicus breeding, however, crossbreeding is an important optimization’s tool used by the livestock producers. Objective. The objective of this study was to determine the behavior of growth characteristics on different proportions of Bos indicus breed crosses. Materials and methods. The analysis was made based on production records of a selected cattle farm with Brahman, Nelore and commercial stock located in the North Pacific region, Costa Rica. The records of 4.294 animals, collected during the 2002-2012 period in the farm, were used; the breed groups included in the study were: Brahman, Nelore, Guzerat, ½ Brahman ½ Nelore, ½ Brahman ½ Guzerat, ¼ Brahman ¾ Nelore, and ¼ Nelore ¾ Brahman. Birth weight, weaning weight, weaning daily weight gain, year old weight, year old daily weight gain, 18 months weight, and 18 months daily weight gain were analyzed according to the breed group of the offspring and the parents. In addition, the non-additive effects (sex, season of birth and year of birth) and their influence on the characteristics were analyzed. Results. It was found that the Brahman, Nelore and ¼ Nelore ¾ Brahman breed groups had the highest weights at all ages, male animals presented higher weights for most of the analyzed characteristics (P <0.05); the animals born in the rainy season presented the highest weights for all the characteristics, in relation to the dry season, while the year of birth did not present trends. The study concluded that the breed group of the mother influenced the early ages of the offspring and the breed group of the father caused differences after one year of age. Likewise, the study concluded that the variables sex and season of birth presented defined behaviors, while the year of birth have fluctuating results. Conclusion. In crossbreds Bos indicus, the breed group of the progenitors have influences in the growth characteristics of progeny.